1. Field of the Invention
This invention relates generally to mandrel apparatus for blow molding machines capable of blow molding a plastic preform into a container, and more particularly relates to mandrel apparatus capable of holding a preform in place against applied forces less than a preselected force.
2. Description of the Prior Art
Presently available mandrels used with blow molding machines are capable of loosely retaining an inverted preform over a pin or projection, with the preform capable of uncontrolled rotational movement about the pin or projection as the preform and mandrel are moved through the blow molding machine. However, with advances in blow molding machines and preforms, such uncontrolled rotation of preforms with respect to the mandrels may be undesirable, in order to assure that a preform has achieved a certain rotational orientation at a selected position during the blow molding process.
Consequently, there exists a need in the art for a mandrel apparatus that is capable of holding a preform in place with respect to the mandrel upon which it is carried, against forces less than a preselected force, yet is capable of permitting movement of the preform with respect to the mandrel to achieve a desired orientation or for removal therefrom upon application of forces greater than the preselected force.